Many such beverages can benefit from or even require chilling in order to preserve or achieve some beneficial attribute. This is especially the case, given the extreme ability of humans to discern even trace amounts of volatile and flavour components, as well as cloudiness or "haze" that forms in some such beverages. Wine beverages for example, can benefit, and specifically so in cases which require remedial processing to deal with, say, excess tartrate concentrations.
Brewery beverages, or fermented malt brewery beverages in particular, are of particular interest because of the special benefits to be accrued by way of "chilling". The general process of preparing fermented malt beverages, such as beer, ale, porter, malt liquor, low and non-alcoholic derivatives thereof, and other similar fermented alcoholic brewery beverages, hereinafter referred to simply as "beer" for convenience, is well known. As practiced in modern breweries, the process comprises, briefly, preparing a "mash" of malt, usually with cereal adjuncts, and heating the mash to solubilize the proteins and convert the starch into sugar and dextrins. The insoluble grains are filtered off and washed with hot water which is combined with the soluble material and the resulting wort boiled in a brew kettle to inactivate enzymes, sterilize the wort, extract desired hop components from added hops, and coagulate certain protein-like substances. The wort is then strained to remove spent hops and coagulate, cooled and pitched with yeast, and then fermented. The fermented brew known as "green" or "ruh" beer is then "finished", aged--which is sometimes referred to as "lagering" and clarified, filtered, and then carbonated) to produce the desired beer.
A variation on the basic process which is now well recognized is termed "high gravity brewing" in which procedure the green beer is produced at an elevated alcohol content (say for example from 7 to 8% v/v, and this is then diluted to the alcohol content desired in the finished beer (eg. 5% v/v for a "regular beer").
As is well known, beers in general develop a haze over time and/or through changes in temperature of the beer. This haze is considered to be made up of two types:
(a) "chill haze" which is temperature sensitive and may disappear as the temperature of the beer is raised to, say, room temperature; and PA1 (b) "permanent haze" which, as the name implies, once created, remains. PA1 "The problems of producing higher strength beers do not stop with fermentation. Long maturation times are required for the removal of "off" flavors and for the development of acceptable flavors and aromas. Furthermore, long periods of cold storage are required to stabilize the beer . . . ". PA1 a) traditionally, by removing the alcohol from a regularly brewed beer by distillation and more recently by ultrafiltration; or, PA1 b) by "cold contact" processing where only minimal fermentation is permitted, such that the alcohol content is at most about 1% v/v and which can be reduced by further dilution to the desired value, usually about 0.5% v/v (volume/volume). (Such a process is described in a variety of patents/applications--Japanese Kokai 53-127861, for example, discloses such a process, as do U.S. Pat. Nos. 4,661,355 and 4,746,518, and published Canadian Patent Application 2,027,651. A significantly improved cold-contact process is disclosed in U.S. Pat. No. 5,346,706. These products have the same haze forming components as regular beers and this is especially so in the cold contact products. Hence they may be advantageously processed according to the present invention. PA1 The present invention was used to produce seven green beer substrate. Evaluations were conducted according to known ASBC industry standards, to determine the polyphenol content (mg/L) of the substrate green beer prior, and subsequent, to the treatment according to the present invention. The results were as follows: PA1 As discussed above, it is considered that a major factor in haze production is the slow precipitation of polyphenyls over time and hence, the reduction thereof by the process of the present invention demonstrates the increased stability of the so treated products as compared with regular beer against chill haze of the products treated according to the present invention. Moreover, the beer exhibited desirable flavour characteristics, especially smoothness. It should be noted that differences in the polyphenol contents are significant.
Of course, if a beer is consumed warm, as is customary in some European countries, then chill haze may not be as serious a problem for the brewer and consumer as it otherwise would be for beers that are customarily consumed cold, (as is typically the case for North American beers, for example).
In any event, the problem of chill haze manifestation has been exacerbated by industry trends that have resulted in an increase in the amount of time that normally elapses between when the beer is finished, and when it is finally consumed by the public. As a consequence the haze has a greater opportunity to develope to a problematic and often unacceptable degree.
The exact nature and mode of formation of haze in beer is still uncertain but it is generally accepted that haze comprises significant amounts of proteins, yeast cells, metals, cell components, polyphenols and various other materials.
The problem of haze formation has been addressed in many ways over many years. The traditional way, of course, is to subject the beverage to a conventional "lagering" step over the course of which the beverage is stored at near zero temperatures for periods of time ranging from weeks to, in extreme cases, up to several months. During this step of the process the yeast cells, proteins, etc., settle out and, all things going well, the taste of the beer may also improve; the beer is said to "mature".
Conventional lagering, however, is not proving to be adequately proactive in keeping pace with the increasing chill-haze problem that results from the longer post-finishing pre-consumption time period mentioned above. Moreover, the time, capital and operating cost commitments associated with the lagering process, account for a significant proportion of the overall brewery costs. Accordingly, significant effort continues to be expended in the search for ways to deal with the chill haze problem, and to find better and less time-consuming alternatives to lagering in general.
Examples of the results of such efforts include the use of polyvinylpyrrolidone (PVP) to stabilize beer by combining with the polyphenyls, which use this is well documented, refer to U.S. Pat. No. 2,688,550; 2,939,791 and others.
U.S. Pat. No. 3,251,693 teaches adding various silicates particularly calcium, magnesium or zinc silicates to the beer (or wart) and U.S. Pat. No. 3,940,498 teaches the use of certain acid treated synthetic magnesium silicates. For example U.S. Pat. No. 3,940,498 teaches adding an acid-treated synthetic magnesium silicate to the beer.
Although these methods do alleviate aspects of the chill haze problem, they by no means eliminate it or replace the lagering process. Moreover these solutions are becoming less favored in the industry, as the use of additives or processing aids in foods becomes less popular with consumers.
Improvements in beverage stability have been mentioned as ancillary benefits in the extensively explored freeze concentration processes. For example, Canadian Patent No. 673,672 involves freezing beer to produce a slurry of concentrated beer, ice and other solids including yeast cells, removing the ice and other solids from the desired concentrated beer, which has concentrated up to five-fold relative to the starting beer. The ice is discarded or passed into a system to recover beer or desirable components entrained thereof on the ice. All freeze concentration processes suffer from the fact that the ice removed can carry away some of the desired material and recovery of that material which is occluded or retained on the ice, by washing extraction or other means, brings its own problems--refer for example to Canadian Patent No. 710,662. Also, the practical process is usually multistage with successive stages being effected at temperatures reduced relative to earlier stages, this procedure being quite common in the freeze concentration art--refer for example to Canadian Patents No. 601,487 and No. 786,308. This latter patent has the same inventor and proprietor as Canadian Patent No. 673,672 and covers products produced by the latter patent. Despite the quite amazing claims made for the products produced under this patent, it does not seem to have ever been commercially exploited. U.S. Pat. No. 4,885,184 teaches a process for preparing flavored malt liquors wherein an aged fermented wort is freeze concentrated generally to the 20% to 30% alcohol by volume level, and various flavorings are then added.
Quite apart from the claims that have been made for accelerated aging and improvements in beverage stability in the freeze concentrated products, there are significant and in some cases insurmountable problems that arise out of collateral concentration of the beer. First of all it is illegal in many jurisdictions to concentrate by distillation or otherwise any alcohol-containing substrate without a distillers or other appropriate license. There is also a fundamental question over whether the product of such a distillation can legitimately be labeled as "beer" at all. Moreover, the stability of freeze concentrated beers appears to be very much in doubt or at least suspect, notwithstanding the various claims that may have been made to the contrary. While any number of attempts have been made to produce concentrated beer products, many have been faced with product instability, as exemplified by work done at the Institute of Brewing Research Laboratories (Essery, Cane and Morris, Journal of the Institute of Brewing, 1947, Volume 53, No. 4; Essery and Cane, ibid., 1952, Vol. 58, No. 2, 129-133; and Essery, American Brewer, 1952, Volume 85, No. 7, 27, 28, and 56). As described in the cited articles, when the concentrated beer was stored and then diluted back to its original concentration, the reconstituted product tasted decidedly weak and underhopped, so that freeze concentration seemed to cause considerable loss of palate-fullness and loss of bitterness. The cited articles also indicate that storage of the concentrate also often actually led to the production of haze and a vinous flavour in the beer.
In the freeze concentration process described in Canadian Patent No. 872,210 the unfermented wort which is freeze concentrated, this apparently providing efficiencies in obtaining a higher yield or extract from the brew materials than is obtained in a regular brew. Because the process is not carried out on an alcoholic substrate, distillation is not an issue. With regard to chill haze, however, any predisposition of a beer to elicit chill haze which is engendered as a result of the fermentation process, will not be addressed by the prefermentation freeze concentration process called for in this Canadian patent.
Another proposal that avoids the problems of distilling an alcoholic beverage, is set out in Australian Patent Specification 224,576. This patent suggests batch freezing a beer to create a slush ice condition. This condition is maintained for up to seventy-two hours and is followed by melting the beer and immediately separating out any precipitated materials. However it is appreciated that the beer contains material which redissolves before it can be removed in the normal course by filtration or centrifugation and consequently the pre-freezing addition of a general adsorbent material such as asbestos or bentonite appears from the teachings of the patent to be critical to the process, so that the precipitated material--eg chill haze material--is adsorbed onto the insoluble additive, before it can redissolve upon melting of the slush. This approach, however, falls back into the problems associated with the use of processing aids and additives as mentioned above, and in particular runs head-long into the prohibition against any food-related use of asbestos in particular. Also, the need to maintain a frozen mass of beer for any protracted period of time appears to be faced with many of the same shortcomings that attend conventional lagering. Moreover, and notwithstanding the collocation of the ice and the beer throughout this process, the fact remains that the aqueous component of the beer is frozen and the balance of the beer is held in a concentrated state. However temporary that condition may be, the fact is that this process necessarily entails concentrating the beer, and is in this connection, merely a batch processing version that is otherwise similar to the continuous process that is described in U.S. Pat. No. 3,295,988--Malick. In both the Australian patented process and the Malick process, the beer is concentrated for a period of time, and then the large amount of frozen aqueous component is melted into the concentrated beer to form the reconstituted beer product from concentrate.
Malick--the developer of the so-called Phillips freeze concentration process, was preeminent in attempts to commercialize freeze concentration technology in beer related applications. According to Malick, (in the article "Quality Variation In Beer" The Brewer's Digest, April 1965), accelerated lagering is caused "because it takes place in a concentrated state". That being the case, the prior art teaches that actual concentration of the beer is a prerequisite to achieving accelerated lagering (with any claimed attendant physical stability benefits).
As indicated above, the occurrence of haze in beer and the management of the lagering process are, obviously, still significant practical problems for the brewing industry, despite the extensive efforts and diversification of the preferred solutions from the past.
Moreover, and notwithstanding Malick's above-quoted assertion that actual concentration is a prerequisite, the present invention has surprisingly revealed that in fact there is no substantive requirement for concentration to take place, and that benefits previously thought to be associated with concentration can be achieved substantially in the absence of such concentration. Moreover, in the case specific of beer, additional advantages with respect to hop flavour retention are realized in applications of the present invention that are not in evidence in the prior art freeze concentration processes.
As indicated, the above detailed discussion centers around alcoholic brewery products and the problems specific to fermented malt beverages. However, there is a need in the alcoholic beverage industry to provide rapid, uniform cooling of alcoholic beverages, usually during processing, to their freezing points, without running the risk of actually freezing to liquid to the point where it cannot be readily handled (ie pumped).